After converting from screenpoint(512, 151) to mappoint, I get the following map coordinates:

338638.7275175141, 4404774.250335829

Now when I perform the reverse conversion (i.e., from the same point above which is mappoint(338638.7275175141, 4404774.250335829) to screenPoint), I get a very different screenpoint (i.e. 31563417740, -72455974). I think I should get the same screenpoint(512, 151) coordinate. For this reverse conversion I am using the following code: